An expert says the coming coronavirus vaccine roll-out could be a "double-edged sword" for New Zealand's wider immunisation rates, with the potential to help or hinder them.
While the Ministry of Health's immunisation programmes have made gains in boosting uptake over recent times, they've generally failed to hit set targets.
The latest coverage rates - for the three months to December 31 - show about 13 per cent of 5-year-olds are not fully immunised.
That included nearly 6 per cent whose guardians had declined vaccinations and 0.6 per cent who'd "opted off" the national register.
The 87 per cent rate was below national targets that aimed for 95 per cent coverage across 5-year-olds, as they also did 8-month-olds and 2-year-olds, whose current coverage rates were 89 per cent and 90 per cent respectively.
Targets of 75 per cent for HPV and influenza vaccinations had also repeatedly not been met, with nationwide coverage for flu sitting at 63 per cent as at May last year.
That stood in contrast to the 90 per cent of the population the Government wants to have vaccinated against Covid-19.
Director general of health Dr Ashley Bloomfield has said 70 per cent vaccination would be the minimum needed for herd immunity, depending on factors including vaccine efficacy.
But polling has suggested only about 70 per cent of New Zealanders would be prepared to get vaccinated, and a further 20 per cent - the "vaccine hesitant" - would get a jab if they were very sure it was safe.
About 10 per cent said they wouldn't.
Border and high-risk workers are set to be vaccinated in March or April, and the general public from around the middle of the year.
The Government aspires to have everyone who wants a vaccination receiving it by the end of the year.
Immunisation Advisory Centre director Dr Nikki Turner said there was no single reason to explain why people didn't get immunised.
"There are a mixture of access barriers, systems issues, and either just a lack of trust or a lack of imperative to act," she said.
"So if you don't see the disease, and you have a whole lot of barriers, and then someone says to you there might be a risk, these things combine to stop somebody receiving a vaccine on time."
Turner, whose group has been involved in preparations for the roll-out, said the coming effort could potentially lift other immunisation rates by addressing long-standing access problems and fostering more public trust.
Turner pointed out that, besides an overlap with the measles catch-up programme, there was no overlap with the childhood immunisation schedule.
"But, as New Zealand as a community understands the place and need for vaccine, that should give us confidence in all of our vaccination programmes," she said.
"If we deliver well, and effectively communicate what we are doing, this does help all of our community understand the science behind vaccines."
She said the Covid-19 crisis had already helped raise awareness around the importance of vaccination.
"This will now be about the system hopefully delivering more effectively, drawing even more attention to it, and making the community more aware so they'll be wanting the vaccine," she said of the roll-out.
"If we can get that mixture right, it'll help the overall programme, but if things go wrong, and we deliver badly, then it could damage it.
"So it's a really interesting question, because it could go each way, but we really hope it will help."
There was early cause for optimism from Israel - one of the first countries to vaccinate against Covid-19 - with its programme already seeing a positive effect.
"It has been a considerable advantage to New Zealand that we have not been the first 'cab off the rank' and we now have not just clinical trial data but also real-world information on vaccine safety," she said.
"This is very helpful to support New Zealanders who have concerns about vaccine safety that we have good safety data now to proceed. How effective it is in the real world, time will tell."
She felt it was important to support the Medsafe process to ensure New Zealand had appropriately gone through a checking process for our own population, and that it wasn't just reliant on international licensure.
Nonetheless, there was good body of data on the Pfizer vaccine New Zealand had pre-purchased, both from pivotal clinical trials and real-world experience on now millions of vaccinees in Europe, the UK and the US.
"To date, the safety data in the real world is good and matches the experience in the trials," Turner said.
"The limiting step now will be securing supplies, but New Zealand's current need is initially quite small because the most urgent need is to protect border staff and MIQ facilities staff.
"Securing these smaller amounts of vaccine supplies is likely to be more feasible than expecting large quantities, as they are wanted urgently in countries who currently have high amounts of disease."